With the Fed expected to further tighten financial conditions following its now guaranteed March 15 rate hike, and the ECB recently announcing the tapering of its QE program from €80 to €60 billion monthly having run into a substantial scarcity of eligible collateral, the third big central bank - the BOJ - appears to have also quietly commenced its own monteary tightening because, as Bloomberg calculates looking at the BOJ's latest bond-purchase plan, the central bank is on track to miss an annual target, by a substantial margin, prompting investor concerns that the BOJ has commenced its own "stealth tapering."

While in recent weeks cross-asset traders had been focusing on the details and breakdown of the BOJ's "rinban" operation, or outright buying of Japan’s debt equivalent to the NY Fed's POMO, for hints about tighter monetary conditions and how the BOJ plans to maintain "yield curve control", a far less subtle tightening hint from the BOJ emerged in the central bank's plan released Feb. 28, which suggests a net 66 trillion yen ($572 billion) of purchases if the March pace were to be sustained over the following 11 months. As Bloomberg notes, that’s 18 percent less than the official target of expanding holdings by 80 trillion yen a year.

Some more details: the central bank forecast purchases of 8.9 trillion yen in bonds in March, based on the midpoint of ranges supplied in the operation plan. Maintaining that pace for 12 months will see it accumulate about 107 trillion yen of debt. At the same time, 41 trillion yen of existing holdings will mature, leaving it with a net increase of 66 trillion yen, well below the stated goal of 80 trillion yen.

And in another potential major shift to the status quo, one which would imply a sharp steepening in the JGB yield curve, the March plan indicates the BOJ may acquire 1.5 trillion yen of bonds due in more than 10 years, down 32 percent from the level in January 2016 when it introduced its negative rate policy. Other parts of the curve are also changed: for one-to-five-year notes, the projection is for an 8.6 percent decline, whereas the central bank will be buying roughly the same amount of five-to-10-year notes.

The BOJ appears to be joining other banks that are seeking to jumpstart the "carry trade" for local banks and pension institutions, by steepening the yield curve. The step-back from buying super-long bonds, those with more than 10 years to maturity, comes after Governor Kuroda and his colleagues said in September that an “excessive” decline in the yields has placed a heavier burden on companies seeking to meet pension obligations.

To be sure, the BOJ could and probably will vary its buying as it attempts to anchor borrowing costs for 10-year bonds at around zero percent, however holding onto both the targets for quantitative easing and yield-curve control has left investors scouring the central bank’s daily purchases to see whether the balancing act is achievable Bloomberg adds.

“If the BOJ was simply to reduce its annual target, it would probably have to do so over and over again, which would clearly look like tapering,” said Naomi Muguruma, a senior market economist at Mitsubishi UFJ Morgan Stanley Securities Co. in Tokyo. If the appearance of tapering isn’t what the Japanese central bank wants, it could replace its 80 trillion yen annual target with one for monthly purchases at its July 19-20 meeting, she said. So far it has not suggested it would do that.

As Bloomberg further adds, "while the BOJ board is projected to keep policy unchanged at its March 15-16 meeting, some central bankers are now considering giving cues on what they’d do with rate policy once inflation starts picking up -- a shift that could end the focus on JGB purchase plans."

With oil prices higher than a year ago and a relatively weak yen, the central bank officials expect the benchmark inflation gauge to be around 1 percent later this year, according to people familiar with the discussions.

The expected pick-up in inflation and rising U.S. Treasury yields have put pressure on the BOJ’s yield-curve control policy. The Japanese central bank offered to buy an unlimited amount of five-to-10-year bonds at a fixed rate on Feb. 3 after borrowing costs surged to the highest in 12 months.

Of course, the BOJ may be simply launching its latest - in the past two decades - attempt at renormalizing the yield curve (all the previous ones have failed). “Given the BOJ is committed to managing the yield curve, any upward pressure on yields could lead to an increase in bond purchases in the future,” said Yusuke Ikawa, Japan strategist at BNP Paribas SA in Tokyo. “If it maintains its zero percent target, the BOJ faces the risk of one day having to buy more than 80 trillion yen of bonds a year.”

Perhaps not surprisingly, local banks are refusing to wait and see what the outcome will be: according to FT parent company, Nikkei Asian Review, Japanese banks are shedding government bonds at an accelerating pace, slashing their total holdings at the end of January to a 14-year low. The value of Japanese government bonds held by domestic banks was 79.59 trillion yen ($693 billion) as of Jan. 31, the Bank of Japan said, falling below 80 trillion yen for the first time since 2003.

Over the past year, Japanese banks were purchasing large amounts of higher-yielding U.S. government bonds, but expectations that President Donald Trump will engage in aggressive fiscal stimulus have produced a spike in U.S. interest rates and sent bond prices plummeting. In response, domestic banks "sold Japanese government bonds to cover the losses," said Kazuhiko Sano of Tokai Tokyo Securities.

Regional banks, relatively weaker in portfolio management, have been prominent in this trend. They amassed net JGB sales of 246.7 billion yen in November and 277.6 billion yen in December, according to the Japan Securities Dealers Association.

As the Nikkei reported last week, this is a concern for the Financial Services Agency, which plans to examine foreign bond investments by regional banks. "It will become tougher for regional banks to invest in overseas bonds," said Katsutoshi Inadome of Mitsubishi UFJ Morgan Stanley Securities.

And so, with both the ECB and BOJ gradually phasing out their support of ultra low interest rates, the unpleasant scenario envisioned last week by SocGen's Albert Edwards may soon come to pass as investors, worried about the removal in central bank backstops, proceed to liquidate holdings en masse, leading to a sharp spike in global yields higher, catalyzing the next leg lower in global risk assets as Goldman warned over the weekend.